package cn.xyy.common.utils;

import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

/**
 * @author https://www.cnblogs.com/nihaorz/p/10690643.html
 * @description Rsa 工具类，公钥私钥生成，加解密
 * @date 2020-05-18
 **/
public class SecretRSAUtils {

	private static final String SRC = "123456";

	public static void main(String[] args) throws Exception {
		System.out.println("\n");
		RsaKeyPair keyPair = generateKeyPair();
		System.out.println("公钥：" + keyPair.getPublicKey());
		System.out.println("私钥：" + keyPair.getPrivateKey());
		System.out.println("\n");
		test1(keyPair);
		System.out.println("\n");
		test2(keyPair);
		System.out.println("\n");
	}

	/**
	 * 公钥加密私钥解密
	 */
	private static void test1(RsaKeyPair keyPair) throws Exception {
		System.out.println("***************** 公钥加密私钥解密开始 *****************");
		String text1 = encryptByPublicKey(keyPair.getPublicKey(), SecretRSAUtils.SRC);
		String text2 = decryptByPrivateKey(keyPair.getPrivateKey(), text1);
		System.out.println("加密前：" + SecretRSAUtils.SRC);
		System.out.println("加密后：" + text1);
		System.out.println("解密后：" + text2);
		if (SecretRSAUtils.SRC.equals(text2)) {
			System.out.println("解密字符串和原始字符串一致，解密成功");
		} else {
			System.out.println("解密字符串和原始字符串不一致，解密失败");
		}
		System.out.println("***************** 公钥加密私钥解密结束 *****************");
	}

	/**
	 * 私钥加密公钥解密
	 * 
	 * @throws Exception
	 *             /
	 */
	private static void test2(RsaKeyPair keyPair) throws Exception {
		System.out.println("***************** 私钥加密公钥解密开始 *****************");
		String text1 = encryptByPrivateKey(keyPair.getPrivateKey(),
				SecretRSAUtils.SRC);
		String text2 = decryptByPublicKey(keyPair.getPublicKey(), text1);
		System.out.println("加密前：" + SecretRSAUtils.SRC);
		System.out.println("加密后：" + text1);
		System.out.println("解密后：" + text2);
		if (SecretRSAUtils.SRC.equals(text2)) {
			System.out.println("解密字符串和原始字符串一致，解密成功");
		} else {
			System.out.println("解密字符串和原始字符串不一致，解密失败");
		}
		System.out.println("***************** 私钥加密公钥解密结束 *****************");
	}

	/**
	 * 公钥解密
	 *
	 * @param publicKeyText
	 *            公钥
	 * @param text
	 *            待解密的信息
	 * @return /
	 * @throws Exception
	 *             /
	 */
	public static String decryptByPublicKey(String publicKeyText, String text)
			throws Exception {
		X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(
				Base64.decodeBase64(publicKeyText));
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.DECRYPT_MODE, publicKey);
		byte[] result = cipher.doFinal(Base64.decodeBase64(text));
		return new String(result);
	}

	/**
	 * 私钥加密
	 *
	 * @param privateKeyText
	 *            私钥
	 * @param text
	 *            待加密的信息
	 * @return /
	 * @throws Exception
	 *             /
	 */
	public static String encryptByPrivateKey(String privateKeyText, String text)
			throws Exception {
		PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(
				Base64.decodeBase64(privateKeyText));
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.ENCRYPT_MODE, privateKey);
		byte[] result = cipher.doFinal(text.getBytes());
		return Base64.encodeBase64String(result);
	}

	/**
	 * 私钥解密
	 *
	 * @param privateKeyText
	 *            私钥
	 * @param text
	 *            待解密的文本
	 * @return /
	 * @throws Exception
	 *             /
	 */
	public static String decryptByPrivateKey(String privateKeyText, String text)
			throws Exception {
		PKCS8EncodedKeySpec pkcs8EncodedKeySpec5 = new PKCS8EncodedKeySpec(
				Base64.decodeBase64(privateKeyText));
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		PrivateKey privateKey = keyFactory
				.generatePrivate(pkcs8EncodedKeySpec5);
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.DECRYPT_MODE, privateKey);
		byte[] result = cipher.doFinal(Base64.decodeBase64(text));
		return new String(result);
	}

	/**
	 * 公钥加密
	 *
	 * @param publicKeyText
	 *            公钥
	 * @param text
	 *            待加密的文本
	 * @return /
	 */
	public static String encryptByPublicKey(String publicKeyText, String text)
			throws Exception {
		X509EncodedKeySpec x509EncodedKeySpec2 = new X509EncodedKeySpec(
				Base64.decodeBase64(publicKeyText));
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec2);
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.ENCRYPT_MODE, publicKey);
		byte[] result = cipher.doFinal(text.getBytes());
		return Base64.encodeBase64String(result);
	}

	/**
	 * 构建RSA密钥对
	 *
	 * @return /
	 * @throws NoSuchAlgorithmException
	 *             /
	 */
	public static RsaKeyPair generateKeyPair() throws NoSuchAlgorithmException {
		KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
		keyPairGenerator.initialize(1024);
		KeyPair keyPair = keyPairGenerator.generateKeyPair();
		RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
		RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
		String publicKeyString = Base64.encodeBase64String(rsaPublicKey
				.getEncoded());
		String privateKeyString = Base64.encodeBase64String(rsaPrivateKey
				.getEncoded());
		return new RsaKeyPair(publicKeyString, privateKeyString);
	}

	/**
	 * RSA密钥对对象
	 */
	public static class RsaKeyPair {

		private final String publicKey;
		private final String privateKey;

		public RsaKeyPair(String publicKey, String privateKey) {
			this.publicKey = publicKey;
			this.privateKey = privateKey;
		}

		public String getPublicKey() {
			return publicKey;
		}

		public String getPrivateKey() {
			return privateKey;
		}

	}
}
